Power converters are connected to an AC or a DC power source for supplying power to an electronic device for a longer time or for supplying power to batteries in the electronic device. However, specifications of the power converters are dependent on the manufacturers so that it is often that different power converters are not compatible. Thereby, the user must carry a dedicated power converter as the electronic device is used outdoors.
Referring to FIG. 4, a prior art is disclosed to improve the inconvenience in the prior art. In that, a connector A is coupled between a power converter and an external device. The resistors or pins B (PIN) are embedded into the connector A. The output voltage of the power converter is changed by changing the resistor. The resistor can be a plug-in type which can be inserted into the connector. Thereby, the user is unnecessary to carry a plurality of power converters.
However, the prior art way has the following disadvantages. In the current commercial notebook, there are at least six voltages are used, which are 15V, 16V, 18V, 19V, 20V, 24V. If it is desired to configure the connectors to present these voltage values, costs in design and development are increased. Moreover, the user must store many resistors so as to make an inconvenience to the users. Furthermore, the adjustment of the resistor values cannot present immediately. This will cause that the device cannot be used or even the device is destroyed.